The spotless smooth-hound (''Mustelus griseus'') is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

houndshark Houndsharks, the Triakidae, are a family of ground sharks, consisting of about 40 species in nine genera. In some classifications, the family is split into two subfamilies, with ''Mustelus'', '' Scylliogaleus'', and '' Triakis'' in the subfamily ...

, in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Triakidae, found on the

continental shelves A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

of the northwest

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

, between

latitude In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north pol ...

s 40° N and 11° N, from the surface to a depth of 300 m. It can grow to a length of up to .

Description

Male spotless smooth-hounds grow to a length of about with females growing to around . The head is short with a fairly long, bluntly pointed snout and the body is slender. The eyes are small and close together. The mouth is long and the lower lip groove is usually longer than the upper one. The teeth are molar-like with low cusps. Both the dorsal fins have a curved trailing edge and the distance separating them occupies about 20% of the total length of the fish. The dorsal surface and flanks are grey or greyish-brown and the ventral surface is paler. The colour is uniform and there are no spots or bands of darker or lighter colour.

Distribution and habitat

The spotless smooth-hound is found in the temperate and tropical Pacific Ocean between 40°N and 11°N, off the coast of Vietnam, Japan, China and Taiwan, and possibly the Philippines. It occurs on the continental shelf and in semi-enclosed areas of sea at depths down to and possibly as deep as . It is found near the seabed, often over sandy substrates and is thought to feed on

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

s and other

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

invertebrates.

Biology

The spotless smooth-hound is

viviparous Among animals, viviparity is development of the embryo inside the body of the parent. This is opposed to oviparity which is a reproductive mode in which females lay developing eggs that complete their development and hatch externally from the m ...

. Males become sexually mature at a length of between and females at . Litter size varies between about five and sixteen pups which are nourished by

yolk sac The yolk sac is a membranous sac attached to an embryo, formed by cells of the hypoblast layer of the bilaminar embryonic disc. This is alternatively called the umbilical vesicle by the Terminologia Embryologica (TE), though ''yolk sac'' is far ...

placentas. The gestation period is about ten months and the pups measure about at birth. Maximum recorded age is nine years.

Status

The spotless smooth-hound is used for human consumption of its flesh and fins which are much esteemed. It is caught using

gillnet Gillnetting is a fishing method that uses gillnets: vertical panels of netting that hang from a line with regularly spaced floaters that hold the line on the surface of the water. The floats are sometimes called "corks" and the line with corks is ...

s, trawls and

longline fishing Longline fishing, or longlining, is a commercial fishing angling technique that uses a long ''main line'' with baited hooks attached at intervals via short branch lines called ''snoods'' or ''gangions''.bycatch Bycatch (or by-catch), in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juve ...

or as a targeted species. It is not known whether the level of fishing is sustainable or whether the population is in decline. The

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

has listed its conservation status of this shark as being "endangered" and considers that further survey work needs to be done to assess population trends and catch sizes.

References

{{DEFAULTSORT:smooth-hound, spotless spotless smooth-hound Marine fauna of East Asia spotless smooth-hound Taxa named by Viktor Pietschmann ru:Американская кунья акула